Conductivity Definition and 382 Threads

Homework Statement Two brass plates, each 0.5 cm thick, have a rubber spacer sheet between them, which is 0.1 cm thick. The outer side of one brass plate is kept at 0 oC, while the outer side of the other is at 100 oC. Find the temperature of the two sides of rubber spacer if the thermal...

Homework Statement I have plate of glass pressed between a hot plate on top and a insulating surface below. The idea is to be able to predict the temperature of the glass plate and the thermal gradient through the plate as well at any time. I know the hot plate is at 400 deg F, that it is an...

I have an relation between permittivity and conductivity as follows: \epsilon(\omega) = 1 + \frac{4\pi\iota\sigma(\omega)}{\omega} Yet am unclear as to how it was derived. Does this relationship have a name and/or derivation to follow through somewhere? also, I believe it is cgs units...

hi, I would appreciate any help i could get on this, thanks. I've to estimate the heat loss from a person, immersed in water at 10ºC if he is wearing a 3mm wetsuit did anyone know how to process? thanks a lot jerem

A wire is 1.0 m long and 1.1 mm2 in cross-sectional area. It carries a current of 5.4 A when a 2.1 V potential difference is applied between its ends. Calculate the conductivity σ of the material of which this wire is made. Known data: I hate Wileyplus. Ok, REAL known data: I know that...

Homework Statement One end of an insulated metal rod is maintained at 100^\circ C and the other end is maintained at 0.00 ^\circ {\rm C} by an ice–water mixture. The rod has a length of 75.0 cm and a cross-sectional area of 1.40 cm^2. The heat conducted by the rod melts a mass of 7.85 g of...

Hi guys, Just like to check with you: How does heat capacity, density and conductivity plays a part in the melting of a certain material. I mean, if a material has a lower heat capacity, while other factors are the same, does that mean it will melt faster compared to one with a higher...

So it has always been my understanding that in order for something to electrically conductive it has to have more electrons than it needs. If the electrons can be easily shaken from their atoms, then it's conductive. The easier it is for the electron to move to the next atom the more conductive...

Homework Statement 1) The inner and outer surfaces of a glass window of area 2.5 m2 are at 22 ºC and 0 ºC respectively. What is the heat lost in 1 second if the glass is 5mm thick and has a thermal conductivity of 1.1 Wm^-1K^-1 ? 2) The same sheet of glass as described in the [above...

Is it possible for plasma to be conducted through a metal wire? I was wondering if you supply the wire with enough plasma to light a low power LED.

Hi I was wondering if I took two peices of copper and held them together then ran a current through the connection what would the resistance of that be? Would it theoritically be zero, but in real life be some very small but insignificant amount? Thanks

Homework Statement At frequency f1=9 GHz, the guide wavelength along a certain dielectric-filled conducting waveguide is found to be Lambda1=3.456 cm, for a particular mode. At frequency f2=10GHz, the wavelength is Lambda2=2.345 cm, for the same mode. (a) What is the cutoff...

Do phonons transfer energy between molecules/electrons within a conductor? If so, how does it happen?

Hey. Is the conductivity of a material related to the dielectric constant (permittivity) in some way? And what about the electrical susceptibility? Thanks

They give me a table of ion concentrations of the most common ions in the cell interior and in the blood. I am asked to calculate the conductivity of the cell interior and that of the blood. I have no idea how to calculate conductivity if I only know the concentrations. Here is the table I am...

Hi, I have read that Thermal Conductivity means: “The thermal conductivity of a substance is the quantity of heat in cal/sec passing through a body 1 cm thick with a cross section of 1 sq. cm when the temperature difference between the hot and cold sides of the body is 1 deg. C.”...

Hello. As you can see, I'm new here. I have a little experience in physics and I've taken through Calc 2 in college. I'm trying to build a portable air conditioning unit. My current design consists of a tub of water with a 6" cube-shaped container of some kind submerged in it containing dry...

I 'trying to find the thermal conductivity of a silicon substrate doped with boron with known dopant concentration. Is there any way to calculate it or it has to be measured. Thanks in advance for any advice.

Does a soluble salt necessarily implies a strong conductivity?

Hello! Could someone please drop a link, a book name or an understandable explanation on what ionic conductivity in solids is? I am a 3rd year Applied Physics student and understand the basic concept, but a deeper description would be interesting for me: for example, how is resistance...

Homework Statement Why doesn't CH3CH2OH (alcohol) conduct electricity but CH3COOH does? Homework Equations The Attempt at a Solution I did some research on the website( answers.yahoo.com/question/index?qid=20080411203909AAqYaN1). It mentions about the difference of bonding...

If I'm given the components of an electrical conductivity tensor, how can I work out the directions in which the current is biggest and the directions in which no current flows?

is it really in super coundactivity the resistance is ZERO and how it become ZERO is it because of law temperature or the applied voltage and does that mean if we have a current in circuit of super conductor it will go for ever or not and why? and why we can not have super conductivity from...

[SOLVED] conductivity of metals Homework Statement http://www1.union.edu/newmanj/lasers/LaserTypes/conductionbands.gif I do not understand this picture. Why does the fact that the valence band for the metal (conductor) is half-filled imply that it has high conductivity?Homework Equations The...

Strangely, this is for a Mat Sci Class. It is probably not as complicated as I am making it out to be, but the book has no suggestions on how to handle this problem. Homework Statement Calculate rate of heat loss through a fireclay refractory wall of wall with thickness .1m. Furnace...

Homework Statement Please stop reading unless you have Kittel's Solid-state physics book. I have the 8th edition. I am working on problem 6.6 "Frequency dependence of the electrical conductivity". Could someone just give me a total rewording of what is going on in this question? For...

Conductivity of a semiconductor charged with "externally added" electrons Hi, how does it influence the conductivity of a semiconducting sphere (I take a sphere as it should make some considerations easier than for a cylindrical wire) if I add external charges to it? Don't know how this...

Homework Statement I'm working through Problem 4.7 in Purcell, on conductivity tensors. We build a conductor by alternately stacking plates of tin and silver (differing conductivities). When we pass a current through this "composite" conductor, we will get a different value for the...

Forgive me if I am posting in the wrong place. I have a problem dealing with thermal conductivity. I have an aluminum plate, approx. 12 in/ long, and 1.5 in. x 4 in on the end which is being applied with 200 W. What I'm interested in is how long it will take before the plate reaches a...

My 8th grade students are doing a comparison of ionic and covalent compounds, comparing their electrical conductivity. We see that water is not a good conductor. So why is it so dangerous to have electricity around water?

Electrical conductivity ?? I have 3 doubts regarding the situation depicted in the attachment (sorry for my bad drawing). The diagram below shows an electrical conductor with the ends mantained at constant potentials (red higher than blue), and current density being shown by the black arrows...

Homework Statement A mountain climber wears a goose down jacket 3.28 cm thick with total surface area 1.10 m2. The temperature at the surface of the clothing is -19.3°C and at the skin is 36.0°C. Determine the rate of heat flow by conduction through the jacket assuming it is dry and the...

Homework Statement A long rod, insulated to prevent heat loss along its sides, is in perfect thermal contact with boiling water (at atmospheric pressure) at one end and with an ice-water mixture at the other. The rod consists of a 1.00m section of copper (with one end in the boiling water)...

edit: not sure why this was moved to homework - it isn't. Hi :) I'm a bit embarrassed to ask this, but I hope someone can set me straight. As a second year university chem student I feel I should know this. In this question about thermal conductivity, I realize that it is a subject to itself...

What does the electrical conductivity of the elements depends from?

Homework Statement It's not a homework problem, but an engineering problem I try to solve before I delve into experimentation :smile: I have a source of heat (SSR - a solid state relay) that's well thermally coupled to the inside of a steel box. The thermal resistance between the SSR and the...

Homework Statement A copper tube, of internal radius 6.959mm, overall radius 7.975mm, thickness 1.016mm, contains water at 68 deg Celsius, and is present in a room with an ambient temp of 26.65 deg Celsius. If the tube is 1000mm long, what will be the rate of heat transferred from the...

Ok, i am given this task by my physics group leader and is required to do an experiment based on the following research question: To investigate the effect of temperature to the conductivity of a charcoal rod. i. How do i heat a charcoal rod to a desired temperature and make it remain...

Is there a way to convert thermal conductivity to the diffusion coefficient? Or is there a way to use the thermal conductivity in Fick's Law?

Hi all, I remember reading somewhere that Cast iron in general has a uniform thermal conductivity k of approx. 47-55, and this remains the same for a wide range of temperatures, im not sure if this is correct, if anyone has any information on this subject, that would be great, if i could...

Homework Statement A cylinder with a piston is filled with ideal gas. The gas temperature is held at 450 K. The cylinder is heated by an oven through a square metal rod connected between the oven and the cylinder. The rod has sides d = 1 cm and length L = 2.3 m. (a) If the oven is held at...

how we determine conductivity of powder?? hmm...i got a question.. i had three inorganic polymer (powder/solid form) and i want to mixed it according to various composition. how can i determine the conductivity? do i need special equipment to read the conductivity or can i just dissolved...

thermal conductivity chart. "K" can someone tell me where i can find the thermal conductivity chart, K it's in the format of J/s m C

This is as I currently understand it: Phonon thermal conductivity is dependent on the phonon mean free path. To define phonon thermal conductivity a mechanism whereby phonons can be brought into thermal equalibruim is required. This is what I have a problem with: Phonon interactions...

I need Info...! Homework Statement I need information on the thermal conductivity of gas . thank you so much . Homework Equations The Attempt at a Solution

In a thermal conductivity table, what does the temperature column represent in respect to the given coefficient "K" ? E.G http://www.engineeringtoolbox.com/thermal-conductivity-metals-d_858.html does it represent the heat capacity of the material?

I think the answer is yes, but I just wanted to check. If you have several sheets of different material, is the total thermal conductivity the sum of the individual thermal conductivities?

...Kay, so I was doing [or trying to do] my homework, and it's pretty basic, actually. We're given a table comprising substances like "vegetable oil", "gatorade", "pencil lead", etc; and asked to predict its electrical conductivity. I tried Googling some of it, but nothing really relevant...

Uhmm.. i faced some problem with my experiment of finding the thermal conductivity of glass..i hope that someone can help me. May i know the extimation of the thermal conductivity of a boiling tube?? isit the same as the thermal conductivity of pyrex glass?? when i want to find the radius...

hey I am doing a chemistry assignment and i can't figure out how to do the following things Account for the difference in the conductivity of 1.)sucrose solution and silver nitrate solution 2.) solid silver nitrate and solid sodium metal 3.) liquid (fused) sucrose and...